Ext.regModel("Image", {
	idProperty: "id",
    fields: [
        {name: "id"},
        {name: "name"},
        {name: "thumb"},
        {name: "full"}
    ],
    proxy: {
        type: 'scripttag',
        callbackParam: 'callback',
        callback: function(){
          console.log('plop');  
        },
        reader: {
            root: 'photos',
            type: 'json'
        }
    },
    callback: function(){
        console.log("load image");
    }
});